1. Field of the Invention
The present invention relates to articles of bedding, and sleeping bags in particular.
2. Description of the Prior Art
Sleeping bags have long been used by campers either for sleeping outdoors or sleeping in tents. Sleeping bags are also utilized indoors when a bed is not conveniently available.
A conventional sleeping bag is typically constructed from thermally insulated sheet-like layers of materials, often filled with thermally insulated padding. A typical sleeping bag is constructed of an expanse of a generally rectangular, multi-ply fabric pad folded linearly in half and having interengageable zipper strips extending about the peripheral, unfolded edges where the unfolded edges of the halves of the folded pad meet. In some sleeping bags the padding on one side of the longitudinal fold may be heavier than on the other and may even include padding to serve as a pillow at the top end. The heavier side of the structure then serves as a bottom mat layer. In any event, even when the layers of material are equally padded, one-half of the expanse of the pad serves as a mat to support the occupant's body from beneath, while the other half is folded over the occupant's body to serve as a main cover.
Conventional sleeping bags are typically constructed so as to keep the occupant warm in chilly, or even very cold, ambient temperatures. Conventional sleeping bags are designed in different weights and with different insulating characteristics depending upon the temperatures of the environments in which they are to be utilized. Nevertheless, virtually all sleeping bags are designed to provide maximum warmth to an occupant for the temperature conditions in which use is contemplated.
However, quite often a sleeping bag will be utilized in ambient temperatures well above the lowest temperature for which the sleeping bag is designed. Under such circumstances, the occupant often becomes uncomfortably warm when covered by the main covering layer of the sleeping bag. In particular, an occupant's feet and legs may become uncomfortably warm due to retained body heat trapped between the layers.
While an occupant can always merely throw back the main cover to cool off, this practice is often unacceptable in environments in which sleeping bags are frequently used. Specifically, when the main covering layer of a sleeping bag is thrown off of the occupant's body, the occupant is subjected to attack by flying and crawling insects. Thus, the occupant is faced with the undesirable choices of remaining beneath the main covering layer of the sleeping bag and thus remaining uncomfortably warm, or exposing his or her body to the annoyance, discomfort, and pain of insects.
A further disadvantage of merely throwing off the covering layer of a conventional sleeping bag is that only the feet and lower legs of the occupant may be uncomfortably warm when encapsulated between the mat layer and the main covering layer of the sleeping bag, while the occupant's upper body may at the same time be quite comfortable. Consequently, if the occupant merely pulls back the top covering layer of the sleeping bag, the occupant's torso may feel chilly, even though the occupant's legs and feet are uncomfortably warm.